The present invention relates to an optoelectric pickup unit that is responsive to that part of a musical instrument that vibrates when the instrument is played.
The standard magnetic pickup has a weak signal and can only be utilized with metal strings, is sensitive to stray fluctuating magnetic fields and has limited frequency response.
U.S. Pat. No. 3,733,953 issued to Mr. Ferber in 1973 discloses an optoelectric pickup that operates on the principal of a string intersecting the path of a light beam from a light-emitting device toward a light-detecting device. Mr. Ferbers' invention has some of the same advantages as the present invention but must still have a complicated sound box with an acoustic speaker, which makes for a large and heavy instrument that is technically difficult to manufacture.
U.S. Pat. No. 05,012,086 issued to Mr. Bernard in 1991 claims to overcome several of the disadvantages of previous optoelectrical pickups but is itself of such a highly technical nature as to be difficult to understand or reproduce.
Pizeo-electric transducer pickups have been devised that overcome some of the deficiencies of the magnetic pickup but these, like most others, require an electrical connection cord and a separate amplifying system.